Tankless water heaters

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Touchdown! Greaser!
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Snorting his way across the USA
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Zero research. Did them on a project once but didn’t do that facet of the design. Had to replace the home water heater. The Other Person brokered the deal and this is how it came out
 
So how do you like it? Our town's water is hard and it eats the tanks. Tanks no longer have that glass lining they used to have to prevent corrosion of the steel tank walls. They're just finished with some sort of hi-temp paint or something.
 
I love my Rinnai tankless. Installed it about 3 years to replace an 80-gallon electric. I out the LP tankless in the garage and gained a whole new closet in the house.

Love the unending hot water and no energy use when we aren’t home. As a bonus, my generator can easily provide the electricity needed for the tankless.

I spend about an hour once a year descaling. Easy peasey.

I would never go back.
 
My current home was purchased with 3 tankless units servicing 4 full/2 half baths and indoor/outdoor kitchen sinks/laundry room (natural gas Rheem units). I was VERY skeptical as I heard it takes a while for hot water to reach the tap and figured I would end up putting in tanks eventually. Turns out, I love them. It doesn’t take much, if any longer, time for hot water to flow and we have endless hot water. If I had to build a new home, I would definitely put them in. I did have to replace one unit due to failure on the emergency heater for the heat exchanger failing and, during a period of sub freezing temperatures for many days the exchanger froze and split (the unit was installed as an exterior unit).
 
I have several tankless at my cabins which are off grid. They work great. One of them needed a booster water pump from an RV which cost $56 extra but I have gobs of hot water instantly. The electric element type use a ton of amps. Usually two or three 60amp breakers for one tankless. I don't have a lot of use through them, but they've been working flawlessly each time I go there.
 
I put a Bosch unit in our cabin about 15 years ago and it's still going strong... no electricity needed and no pilot, it has a little turbo generator that generates electricity for the controls and ignition from the water flow. Then installed a larger Rheem unit in the house a couple of years ago, that one needs electric but so does the well pump anyway. Both are LP. I'll never go back to tanks.
 
The only complaint I have with the one I use is that the kitchen sink faucet can’t be throttled down to eliminate spray while rinsing dishes and still provide not cold water.
 
I installed one in our RV. Tankless makes sense in RV's because tanked water heaters are typically 10 gal or less. In the RV it saves weight and provides endless hot water. The caveat is I have had to repair the thing multiple times. It has experienced board failure, sensor failures, fan failure, etc.

When the fan fails is particularly interesting. The fan brings in fresh air to the combustion area and exhausts combustion gases. When the fan fails it starves for oxygen and the flame goes out; the water in your shower goes cold. You turn the water off, then back on. The water heater attempts restart but doesn't have oxygen to reignite. Each time a restart attempt occurs some propane is released into the combustion area. Cold in the shower you turn the water on again hoping for hot water. At this point you hear a boom as there is now enough oxygen for it to ignite again; a fireball is shot out of the side of your RV water heater.

In spite of the aforementioned issues, I advocate for tankless water heaters in RV's as the benefits outweigh the drawbacks. When we had apartments I looked into tankless water heaters as a possible replacement for the large commercial tanked water heaters we had. If you get 200k BTU or more an annual boiler inspection may be required. Proper sizing is key with these units. Before buying you want to consider your incoming water temp, desired water temp, figure the rise required and GPM required. As mentioned previously, the electric only models require alot of power; you will likely need ng or propane.
 
I've had one in a rental that been working great for 10 years. Only have to change a single D cell for the ignitor every year. We have extremely acid water, and the copper exchanger is holding up fine, but the flow control valve is starting to get stiff. It's an Excel brand, bought it off Ebay so finding parts may be problematic. They still have a distributor in FL, but customer service is unresponsive.
 
Put a tankless in back in 2016 when I built my house. Also put in a steam shower with a bench. Highly recommend.
 
Somehow, living in a geologically active area having 50 gallons of potable water in my basement gives me a warm fuzzy. Would definitely put one in a rental.
 
Bought a vacation home w/ one that didn't work; replaced it a new one that failed soon. Gave up and put in a 25 gal tank. Not likely to try again.
 
Tankless concern me about legionella (I’ve seen too many of them installed at point of use instead of a proper hot water system with tempering valves in commercial settings). But I would like to have a mini “boiling water” tanked system under my kitchen sink. When I was a kid my grandparents had a boiling water tap in the kitchen (one of my uncles had built it as a science fair project in the 1960’s). It was usefull as all get out, boiling potatoes? Instantly boiling hot water in the pan, put it on the stove and it boiling, making coffee? Put the grounds in and fill the dripper, want a boiled egg, just put it in a pan and fill it, when it was cool enough to take out it was done, that thing was awsome but could never be marketed because of liability issues.
 
Flatiowa said:
Tankless concern me about legionella (I’ve seen too many of them installed at point of use instead of a proper hot water system with tempering valves in commercial settings). But I would like to have a mini “boiling water” tanked system under my kitchen sink. When I was a kid my grandparents had a boiling water tap in the kitchen (one of my uncles had built it as a science fair project in the 1960’s). It was usefull as all get out, boiling potatoes? Instantly boiling hot water in the pan, put it on the stove and it boiling, making coffee? Put the grounds in and fill the dripper, want a boiled egg, just put it in a pan and fill it, when it was cool enough to take out it was done, that thing was awsome but could never be marketed because of liability issues.
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The bride bought an 'instant hot' kettle which I believe is an invection process. However it works, it works great. Heats a quart of water to boiling in about 90 seconds. Almost as good as an insta-hot tap without the plumbing and electric install.
 
Chip Sylverne said:
The bride bought an 'instant hot' kettle which I believe is an invection process. However it works, it works great. Heats a quart of water to boiling in about 90 seconds. Almost as good as an insta-hot tap without the plumbing and electric install.
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I don't know which kettle you have, but the term is "induction". And, yes, they can be very fast!
 
I guess in theory you are saving on gas because you aren't constantly heating the unit, but for 6+ AMU's I doubt I'll ever get a return. The water heater's usage is only about five or six dollars a month. It must be pretty efficient though - the vent gasses are so cool that they use a plastic vent with a condensate drain.
 
172andyou said:
I don't know which kettle you have, but the term is "induction". And, yes, they can be very fast!
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Invection, induction, both cause heat, right?
Too much election, not enough flying.
 
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